Currently, conventional communication systems for network match-up games, which enable a communication match-up over the Internet have been proposed. In such communication systems, a terminal device used by a user first connects to a server device called a lobby server and is subsequently introduced to a match-up counterparty. After the match-up counterparty is set, terminal devices establish peer-to-peer communication to conduct a communication match-up game, and when the winner and the loser are determined, the match-up result is sent to the server device. Moreover, from the standpoint of popularization of an in-home LAN (Local Area Network) and of a network security, the terminal device generally connects to the Internet through a router device, a firewall, etc.
In such communication systems for a communication match-up game, when a player is not satisfied with a match-up result, the player may perform a malicious action such as, for example, the player changing the setting of the router device or the firewall connected to the terminal device used by the user, or disconnecting the connection thereto in order to sabotage the communication link with the counterparty, thereby invalidating the match-up result itself Such action is called a “cheating action”.
A technology of detecting such a cheating action is disclosed in patent literature to be discussed later.
Because it is difficult for a player to rewrite the program of a game in some cases, the player may carry out a cheating action by disconnecting a wire connection to the router device or by turning off the power of the router device to disable a connection to the Internet. Patent Literature 1 specifies where the cause of a communication failure is present in a terminal device performing a match-up and how to cope with such action.
That is, each terminal attempts to establish communication with other communication devices like a lobby server when a communication fails while a terminal device is conducting a match-up with the terminal of a match-up counterparty. When succeeding in such an attempt, the terminal device determines that the terminal device of the match-up counterparty had some type of failure, and when failing such attempt, the terminal device determines that the failure occurred between the local terminal device and a computer communication network. According to such technology, the presence/absence of such a failure can be a criterion for determining whether cheating by a user has occurred.
Patent Literature 1: Unexamined Japanese Patent Application KOKAI Publication No. 2005-130166